Cadmium Plating Follow up

One issue I have been dealing with is tight threads. All of the plated screws and nuts go together very hard or will not go together at all. Taps and dies have been purchased for all the threads I have encountered on the bike; BSW, BSF, BSC and a number of odd ball threads such as 13/16 -20 & 9/16-20. These taps and dies have mostly been found on ebay. I have gotten into the habit of running a tap and die into every nut and on each bolt before putting things together. This takes off the new cad plating but leaves the original cad film in most cases. Threads work great. I have been holding all bolts and studs in a lathe and then hand tapping them while nuts go in a small aluminum jawed machinist vice.

My “plan B” for parts that missed the plating process was to paint them with a finish similar to cad. A “high temperature ceramic aluminum header paint” was found at my local “Autozone” that fits the bill. While I would much rather have cad this will work for now. When I send parts out for my next restoration they will go too if the paint does not hold up.

Rebuilding the Transmission

The transmission was pretty used up on the Hornet. Gears were abraded and worn to the point I did not want to use them. A person was parting out a ’66 on ebay and a complete transmission was purchased which was in great shape. While everything was apart the needle and roller bearings were replaced. The bronze bushings looked good. The BSA factory workshop manual was a nice guide for putting everything back together and for explaining what size shims to use and where. Once assembled, I checked the end play to assess the shims. The layshaft had .02 end float which was excessive. I installed the mid size shim BSA made and put the float at .005 which should be good. Optimal is .002 from what can be found on the internet.  It runs through all of the gears and should be a good transmission for this bike.

The original transmission above & below. 

17 (stock), 20 & 21 tooth final drive sprockets. I will be using the 21 to keep the revs down at highway speeds, which has been a problem on my '70 Lightning with a 20 t sprocket. 

One thing that works work well when replacing bearings is to heat the aluminum up to 350F in the oven. My wife is not real fond of this but has not thrown me out of the house for doing it….yet. The bearings come out very easy when the cases are heated up. I install them in the same manner. This came in handy for the needle and roller bearings and was used for the steel pinion crankshaft gear too.

New bearings installed. 

An additional point of focus was to clean up the shifter plate. The one purchased on ebay looked good but was bent. It must have been a common problem since the '67 plate was much heavier. I polished up the '67 plate as it was a little scraped up. This included polishing the detent surface as well as the track the shifter dogs slide in. I did not remove much material and only cleaned up the rough spots.

Rebuilt & ready to go in the case. 

The Oil Pump

The oil pump tach drive was broken off and there was a small chip out of the die cast body. A used one was purchased on ebay that looked good but would not turn free. I tried to fix this with poor results and ended up taking the tach drive off of the ebay pump to put on my old one. The worm gear was worn and a NOS one was bought from an internet site. It was rusted a bit but cleaned up alright. One issue was that the threads did not go all the way through and it would not start onto the shaft. I am now the owner of a 9/16 – 20 LH tap which was used to remedy the issue. The gear is case hardened but it tapped alright. I am sure it was not good for the tap as it squeaked all the way through the hole.

To test the pump I hooked it to a drill per Mike Brown’s “Building a Better BSA” video and pumped oil through it. A quart went through pretty fast which means it should work fine. There is not an oil pressure gage on the ‘67 so pressure could not be checked. An internet site from a shop in Howard City Michigan, E & V Engineering, gave a run down on checking a BSA oil pump when you have no gage. Oil should pump out of the crank bearing and there should be output from the scavenge side.  The line to the head also pumped oil. Check out the notes on E & V’s site for more info. I will put the bike in gear, take out the plugs, and push it down the driveway before starting it to make sure oil flows back into the tank, but I should be good to go. 

Rebuilding the Engine

This is one of the first things I started although I just finished it. The Hornet had matching numbers and I wanted to make sure the engine cases were good before spending a lot of time and money on the bike. After cleaning and soda blasting everything I measured all of the key components. The crankshaft journals and main bearing were worn out of spec while the connecting rod small ends looked good. The timing side camshaft bushings were also out of spec. The cylinder bores had .01 inch of taper in them too. Precision engine machining is an area I decided to let the experts tackle. I took the engine and its components to Expert Motorcycle Works in Hobart Indiana.  They had new cam bushings put in and honed to size. They did not do the breather end as this measured within spec. They bored the cylinder out .020, ground the crank and installed a new crank bushing which was honed to size. I also had them put new bearings on the crank and in the case.  The bike was left to sit for several months while I collected parts, saved money and worked on other things.

 The first thing I did after getting the engine back from Expert Motorcycle Works was to shim the crankshaft. This was not too difficult but took a lot of time as I had not done it before. I setup the crank with the original shims and it measured .005 in of float. BSA spec is .002 so I added a .003 shim and rechecked it. I had to purchase a bearing separator for the job which I found at Harbor Freight. It worked well.

Mike Brown’s “Building a Better BSA” DVD gave me a lot of pointers which I gladly followed. One was to install the countershaft sprocket before assembling the cases. This made the task much easier than I have found it to be in the past. I had to install high gear to accomplish this so I decided to go through the transmission at that time also. I will discuss this in a later post. Honda 4 gasket maker was used to seal the cased together and grease was used to hold the crankshaft thrust bushing in place. This went well and was uneventful. After sealing the case the end play was still at .002 in.

I elected to put the primary and transmission sides together before putting on the cylinder. Using this method I was able to put a rod through the piston small end bearings to torque engine nuts. This is much simpler than wrapping a chain around the drive sprocket. I purchased a set of motorcycle ring clamps to assemble the top end. Money well spent although big pipe clamps would probably work too.